Surfacing material for roads.



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GHAELES M. UPI-1AM, 0F STOUGHTON, MASSACHUSETTS.

SUBFAC ING MATERIAL FOR ROADS.

No Drawing.

To all 'wlzc'm it may concern:

Be it known thatI, CHARLES M. UPHAM, of Stoughton, in the county of Norfolk, and in the State of Massachusetts, have invented a certain new and useful Improvement in Surfacing Material for Roads, and do hereby declare that the following is a .full, clear, and exact description thereof.

The object of my invention has been to provide an improved surfacing material for roads which shall have, among others, the following advantages:

That it can be made of any natural aggregate, so long as it does not contain too large stones, and can,therefore, use any earthy material or mineral matter which may be found available nearest the location of the road upon which it has to be laid; that it shall not become soft and spongy during I cal only of hot weather, and shall not become brittle in colt weather, and that it shall, therefore, be cheap and durable; and to such ends my invention consists in the surfacing material for roads hereinafter specified.

While I have illustrated my invention by the best embodiment thereof known to me, such embodiment is to be regarded as typimany possible embodiments, and definite statements are to be regarded as illustrative only, and capable of wide variation.

My invention relates to that class of roads in which a bituminous surface material is used having a natural aggregate. Such roads consist of a bituminous binder and an earthy or mineral material mixed therewith and called an aggregate.

I have desired to provide a surfacing material in which any available earthy or mineral material could be used as the aggregate; this enables the material of an old road, being made over, to beused, or rock, sand or soil in the immediate neighborhood to be used. Prior to my invention, so far as known to me, all road surfaces using a natural aggregate with a bituminous binder becomes soft and spongy in hot weather and thus increase the effort to draw a load thereon. Moreover, by softening in this way, the tendency of particles of the road to be torn away from the road bed is greatly increased; Moreover, such prior roads become brittle at lower temperatures and'tend to disintegrate. 1

. According to my invention, with a relatively high melting point and I use abinder Specification of Letters Patent. Patemtqgd Sept is, 191?, Application filed June as, 1912.- Serial No. 706,517.

had either dry steam or air blown through 1 it while in a fluid condition. This makes it less susceptible to temperature changes, that it does not become brittle even at low temperatures. The quality of resistance to high temperatures or the low penetration is obtained by greater distillation, that is, by distilling ofi the lighter products. This process also increases the degree of the melting point. The penetration refers to the extent to which an object, such as a needle of a given size, will penetrate the bitumen under a given weight in a given time. As a specific instance of a binder which I find to work advantageously, one having a melting point of 150 F., and a penetration, when measured with a standard penetrometer (Dow) fitted with a No.2 needle weighted with a 100 gram weight applied for five seconds with the bitumen maintained at 77, shall not be more than 55. The figures given in this specific instance are only given for the purpose ofstating a specific example, and it is to be understood that they are capable of, very wide variation.

In making a surfacing material, I mix with whatever available earthy or mineral material there may be, a suitable quantity upon the binder to give the pavement stability, and not depending upon the form of the aggregate'for that purpose.

I find that if the pavement is not sulficiently dense, aggregate is too coarse, I can substantially increase the densitv bv the addition of finer material, such as dust, silt, pulverized clay, soil or similar very fine material. The proportion of this fine material may be as great as two-thirds of the proportion of the aggregate.

In building a road, using my invention, the sub-grade of the road is shaped and compacted by any desirable means, so as to present a surface free from depressions owing to the fact that the dust, screenings, mineral chips, slag, or other mineral grit is preferably spread upon and rolled into the surfacing. This gives the surfacing a tooth and prevents it becoming slippery.

I claim:

1. A surfacing material for roads comprising a bitumen having a melting point of substantially 150 F. and a penetration not substantially more than measured with a Dow penetrometer with gram weight at a temperature of 77 F.

2. A surfacing material for roads comprising a bitumen having a melting point of substantially F. and a penetration not substantially more than 55 measured with a Dow penetrometer with 100 gram of substantiall weight at a temperature of 77 F, and a natural aggregate.

3. Asurfacing material for roads comprising a bitumen having a melting point not substantia y more than 55 measured with a Dow penetrometer' with 100 gram weight at a temperature of 77 F. and a natural aggregate comprising a large proportion of fine material mixed with larger material.

In testimony that I. claim the foregoing I have hereunto set my hand.

CHARLES M. UPHAM.

Witnesses:

FRANCIS A. Rosanna, 1 A. M. GoRMAN,

150 F. and a penetration 

